A recent increase in targeted attacks using chemical warfare agents by dictators and authoritarian regimes against politicians, journalists, and other civilians is a major concern. To aid the civil investigators in identifying poisonous substances in such cases, we developed an algorithm and a lightweight and simple-to-use software, ToxicMassSceptic, with a database of 400 electron ionization mass spectra entries, which include many poisonous and explosive agents. The identification relies on a window-based reduction of the experimental spectra and four statistical metrics that are combined into a single metametric. The software also features automatic spectral background removal. Furthermore, we provide the workflow for increasing the size of this database by performing theoretical calculations of mass spectra with a molecular dynamics-based approach. The accuracy of both the theoretical prediction workflow and ToxicMassSceptic is validated on the experimental spectra. Our results demonstrate that the proposed software package can aid in the preliminary identification of traces of poisonous and explosive substances.